The objective of this project is the further development of the MGH Transverse Section X-ray Camera to permit the collection of gated high resolution cardiac images. The sequential images thus produced should allow the demonstration of heart kinetics, permit better visualization of tissue abnormalities and allow computation of physiological parameters such as cardiac output and ejection fraction. The project includes derivation and testing of different data collection methods by computer simulation and phantom studies, methods to reduce artifacts in the reconstructed image due to heart motion and lung motion, and development of the necessary hardware and software to produce gated images and calculate heart function parameters.